Thank you, Swordofury. What makes me curious is that until today, I have never seen those. And now that I've seen your explanation, I am sorry to say that I clicked the "This is offensive" thing in front of my comments to see what would happen. When it made the first comment disappear, I clicked the second one to get rid of it!

We all know oxymorons like 'jumbo shrimp,' (a phrase that contracdicts itself. These were fun, but they're not oxymorons, they're semantic synonyms - they don't contradict, they only rephrase an original noun.